JPH05340615A - Freezer device - Google Patents

Abstract

PURPOSE:To prevent liquid at the time of energization from being compressed at a freezer device in which the liquid is injected into a compressor so as to restrict increasing of temperature of discharged gas. CONSTITUTION:Within a freezing circuit are arranged the first injection circuit 19 for reducing a pressure of refrigerant liquid in a high pressure refrigerant liquid line 36 with the first capillary tube 21 and injecting the refrigerant liquid to an intermediate pressure part of a compressor 1 and the second injection circuit 20 for reducing a pressure of the refrigerant liquid with the second capillary tube 22 and injecting the refrigerant liquid to a refrigerant gas suction line 31. The first and second injection circuits 19 and 20 are commonly connected in series at their upstream side in respect to the first capillary tube 21 and the second capillary tube 22, thereby both injection circuits 19 and 20 are concurrently operated or non-operated under an operation of a solenoid valve 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to suppress the temperature rise of discharge gas and compressor lubricating oil by injecting a refrigerant liquid into an intermediate pressure portion of a compressor and a refrigerant gas suction line during a refrigerating operation. Refrigeration equipment.

[0002]

2. Description of the Related Art A typical prior art of a refrigerating apparatus provided with an injection circuit for injecting a refrigerant liquid for the purpose of lowering the temperature of gas discharged from a compressor and the temperature of lubricating oil is, for example, JP-A-59-217458. It is known from the publication. FIG. 2 shows an outline of a refrigeration system including an injection circuit. This refrigerating apparatus includes a compressor 1, a four-way switching valve 2, a condenser 3, an expansion mechanism 4 including a temperature-sensitive expansion valve, an evaporator 5, and an accumulator 8, and further includes a defrost capillary 7 to perform a normal refrigeration cycle. A refrigeration circuit is formed in which the refrigerating operation and the defrosting operation by the reverse refrigeration cycle are switched. The oil separator 6 has an oil outlet connected to the outlet side of the accumulator 8 by a conduit having a capillary 33. The defrost capillary 7 is connected to the inlet of the temperature-sensitive expansion valve 4 via a dryer 11 and a filter 12 in series. For this defrost capillary 7, a check valve 9 and a receiver 10 are provided.
The pipelines having and connected in series are connected in parallel. The check valve 13 is connected in parallel to the expansion valve 4. The evaporator 5 is connected at its coil end, which is on the outlet side during cooling, to the second switching port of the four-way switching valve 2 via the check valve 14. A heater conduit having a drain pan heater 17, heaters 16 and 16 for internal fan, and a check valve 15 in series is connected to the check valve 14 in parallel. Internal fan 24,2
4 is cooled to a low temperature by the latent heat of vaporization of the evaporator 5. On the other hand, in the condenser 3, the high-pressure refrigerant gas is exchanged with the outdoor air flowing with the rotation of the outdoor fan 23. The latent heat of condensation is heat-exchanged to be condensed and liquefied.

In FIG. 2, a first injection circuit 19 and a second injection circuit 20 are branched from a refrigerant liquid line. The first injection circuit 19 includes a first electromagnetic valve 26 provided in a thin tube 25, and when the first electromagnetic valve 26 is opened, a small amount of the refrigerant liquid flowing through the refrigerant liquid line is introduced, and the compressor is a scroll compressor. The refrigerant liquid is injected into the scroll intermediate portion (which becomes the intermediate pressure portion) of No. 1 to operate so as to cool the compressed gas in the scroll.

On the other hand, the second injection circuit 20 is
The second electromagnetic valve 28 and the capillary 27 are formed in a refrigerant pipe line connected in series, and a small amount of the refrigerant liquid in the refrigerant liquid line is introduced by opening the second electromagnetic valve 28, and after the pressure is reduced by the capillary 27, the accumulator 8 By injecting the refrigerant liquid into the refrigerant gas suction line connected to the refrigerant inflow side, the lubricating oil accumulated in the accumulator 8 is cooled.

[0005]

The injection circuits 19 and 20 are provided with the solenoid valves 2 while the compressor 1 is stopped.
6, 28 are closed to make them inoperable. However, if there is even a slight leak in the solenoid valves 26, 28, especially in the case of the first injection circuit 19, the inlet / outlet of the solenoid valve 26
Due to the pressure difference in the outlet pipe, the refrigerant liquid passes through the solenoid valve 26,
There is a problem that when the compressor 1 flows and stays in the scroll of the compressor 1 and is started immediately after that, the compressor 1 causes liquid compression and damages of the scroll.

An object of the present invention is to prevent the refrigerant liquid from staying in the compressor even if a refrigerant leak occurs in the liquid injection circuit connected to the compressor when the compressor is stopped, thereby preventing the liquid compression at the time of start-up and ensuring safety. It is to provide a refrigerating device having high property.

[0007]

The present invention relates to a refrigerating apparatus having a refrigerating cycle including a compressor 1, a condenser 3, an expansion mechanism 4 and an evaporator 5, and a refrigerant inflow side of the expansion mechanism 4. The first injection circuit 19 for guiding the refrigerant liquid in the high-pressure refrigerant liquid line 36 connected to the compressor 1, decompressing it with the first capillary 21, and injecting it into the intermediate pressure portion of the compressor 1.
And a second injection circuit 20 for guiding the refrigerant liquid in the high-pressure refrigerant liquid line 36, decompressing it by the second capillary 22, and injecting it into the refrigerant gas suction line 31 connected to the refrigerant outflow side of the evaporator 5, An electromagnetic valve 18 that is shared by the first and second injection circuits 19 and 20 and is connected in series upstream of the first capillary 21 and the second capillary 22 and that is closed when the compressor 1 is stopped. It is a refrigerating device characterized by the above.

The present invention is also a refrigerating apparatus in which the solenoid valve 18 is opened so that the first and second injection circuits 19 and 20 are always injecting operation during the refrigerating operation.

[0009]

According to the present invention, both the injection circuits 19 and 20 are simultaneously operated during the refrigerating operation, and the refrigerant liquid injection action by the first injection circuit 19 suppresses the abnormal rise in the temperature of the discharged refrigerant gas. Further, due to the refrigerant liquid injection action by the second injection circuit 20, the temperature rise of the lubricating oil present in the refrigerant liquid storage portion such as the accumulator in the low pressure suction line is suppressed.

When the electromagnetic valve 18 is closed when the compressor 1 is stopped and both injection circuits 19 and 20 are in the inoperative state, even if a slight leak may occur in the electromagnetic valve 18, Since the intermediate pressure on the compressor 1 connection side of the first injection circuit 19 is higher than the low pressure on the suction line connection side of the second injection circuit 20, the refrigerant liquid accumulated in the compressor 1 is 1 injection circuit 19 to 2nd injection circuit 20
The pressure difference causes the gas to flow toward, and the refrigerant gas also flows in the same manner. Therefore, the refrigerant liquid does not collect in the compressor 1, liquid compression does not occur at the time of starting, and safe operation is possible.

According to the present invention, the solenoid valve 18 is operated during the freezing operation.
Even if you always open the first and second capillaries 2
Since 1 and 22 have a large resistance to the refrigerant gas, the amount of the refrigerant flowing by bypass is so small that it can be ignored.
Therefore, there is almost no decrease in the refrigerating capacity, and the control for suppressing the temperature rise of the discharged gas is stably performed.

[0012]

1 is a refrigerating circuit diagram in a refrigerating apparatus according to an embodiment of the present invention. The refrigerating apparatus shown in FIG. 1 includes a compressor 1, a four-way switching valve 2, a condenser 3, an expansion mechanism 4 including a temperature-sensitive expansion valve, an evaporator 5, and an accumulator 8, and further includes a defrost capillary 7, A refrigeration circuit is formed in which the refrigeration operation by the refrigeration cycle and the defrost operation by the reverse refrigeration cycle are switched.

A scroll compressor is used as the compressor 1. The compressor 1 has a discharge port connected to an inflow port of the four-way switching valve 2 by a conduit 29 having an oil separator 6 and an intake port. It is connected by a line 30 to the outlet of the accumulator 8. The inlet of the accumulator 8 is connected to the outflow port of the four-way switching valve 2 by the pipe 31. on the other hand,
The oil separator 6 is connected to the outlet side of the accumulator 8 by a pipe 32 having an oil take-out port having a capillary 33.

In the condenser 3, the coil end on the inlet side during cooling is connected to the first switching port of the four-way switching valve 2 by the pipe 34, and the coil end on the outlet side during cooling is connected by the pipe 35. It is connected to one end of the defrost capillary 7.
The other end of the defrost capillary 7 is connected to the inlet of the temperature-sensitive expansion valve 4 by a refrigerant liquid line realized by a pipe line 36 having a dryer 11 and a filter 12 in series. The defrost capillary 7 is connected in parallel with a pipeline having a check valve 9 and a receiver 10 connected in series.

An outlet of the temperature-sensitive expansion valve 4 is connected to a coil end of the evaporator 5 on the inlet side when the evaporator 5 is cooled by a pipe line 37. A check valve 13 is connected in parallel to the expansion valve 4. The evaporator 5 is connected to the second switching port of the four-way switching valve 2 by a pipe 38 having a coil end, which is on the outlet side during cooling, via the check valve 14. For the check valve 14, a drain pan heater 17, an internal fan heater 16,
16, heater lines having check valves 15 in series are connected in parallel. In the refrigerant liquid line 36, a pipe 39 extends from a portion near the defrost capillary 7 on the way, and an inlet of the solenoid valve 18 is connected to an end of the pipe 39. The outlet of the solenoid valve 18 is connected to the inflow side end of the first injection circuit 19 and the inflow side end of the second injection circuit 20.

The first injection circuit 19 is provided with a first capillary 21, the end of which on the outflow side is connected to the intermediate pressure portion of the scroll in the scroll compressor 1. The second injection circuit 20 includes a second capillary 22, and an outflow side end portion of the second injection circuit 20 is branched and connected to, for example, a pipe line 31 in the refrigerant gas suction line.

In the refrigerating apparatus of the above embodiment, the compressor 1, the oil separator 6, the four-way switching valve 2, the condenser 3, by changing the four-way switching valve 2 to the valve operation shown by the solid line in FIG. The refrigeration cycle of the check valve 9, the receiver 10, the dryer 11, the filter 13, the temperature-sensitive expansion valve 4, the evaporator 5, the check valve 14, the four-way switching valve 2, the accumulator 8, and the compressor 1 is formed,
The indoor air flowing with the rotation of the internal fans 24, 24 is cooled to a low temperature by the latent heat of vaporization of the evaporator 5, while
In the condenser 3, the high-pressure refrigerant gas exchanges heat of condensation latent heat with the outdoor air that flows with the rotation of the outdoor fan 23 to condense and liquefy.

On the other hand, when the evaporator 5 is to be defrosted, the compressor 1, the oil separator 6, the four-way switching valve 2 and the check valve 1 are switched by switching the four-way switching valve 2 to the operation shown by the broken line.
5, inside fan heater 16, drain pan heater 17,
Evaporator 5, check valve 13, filter 12, dryer 11,
A defrost cycle of the defrost capillary 7, the condenser 3, the four-way switching valve 2, the accumulator 6, and the compressor 1 is formed, and the evaporator 5 side is defrosted by the visible and latent heat of the hot gas.

While the compressor 1 is operating during the freezing operation, the solenoid valve 18 is opened to operate the first and second injection circuits 19 and 20. The first injection circuit 19 guides a part of the refrigerant liquid flowing through the high-pressure refrigerant liquid line 36 to reduce the pressure to an intermediate pressure by the first capillary 21, and the reduced pressure refrigerant liquid is applied to the scroll intermediate pressure portion of the scroll compressor 1. To inject. This liquid injection suppresses an abnormal rise in the temperature of the discharged refrigerant in the compressor 1.

On the other hand, the second injection circuit 20 is
A part of the refrigerant liquid flowing through the high-pressure refrigerant liquid line 36 is guided, reduced in pressure to a low pressure by the second capillary 22, and the reduced pressure refrigerant liquid is injected into the accumulator 8 via the refrigerant gas suction line 31. Due to the cooling action by this liquid injection, the temperature of the lubricating oil sent into the accumulator 8 via the pipe 32 is lowered. The lubricating oil whose temperature has dropped is guided to the low-pressure refrigerant gas flowing through the pipe 30 and sent to the compressor 1.

When the compressor 1 is stopped, the solenoid valve 18 is closed. By closing the solenoid valve 18, the injection action of both injection circuits 19 and 20 is stopped. In this case, as described above, the refrigerant on the compressor 1 side moves to the accumulator 8 due to the pressure difference between the injection circuits 19 and 20.

As described above, it is desirable that the electromagnetic valve 18 be opened while the compressor 1 is in operation, but closed when the temperature is abnormal as the discharge gas temperature decreases.

The second injection circuit 20 is
It may be connected to any place in the refrigerant gas suction line 31 that connects the outlet of the evaporator 5 and the suction side of the compressor 1, but it is lubricated to be connected to the inflow side of the accumulator 8 that temporarily stores the liquid refrigerant. It is preferable for enhancing the cooling effect of oil.

In the embodiment shown in FIG. 1, when defrosting is performed by the reverse cycle, the high pressure refrigerant on the side of the condenser 3 is switched to the four-way switching valve 2 immediately after the cooling operation is switched to the defrosting operation when the outside air temperature is high. It may be sucked into the compressor 1 through the accumulator 8, and as a result, the discharge pressure of the compressor 1 further rises, and a protective device such as a high pressure switch is often activated to stop the operation.

Therefore, when the defrost start signal is issued, the four-way switching valve 2 is switched to the defrost cycle side, and at the same time, the compressor 1 is controlled to be stopped for a predetermined time, for example, 15 seconds, and then started. In this way the compressor 1
When is stopped, the refrigerant accumulated on the side of the condenser 3 during that time diffuses to the low pressure side and the pressure drops, so it is possible to prevent an abnormal increase in high pressure during defrost startup.

[0026]

As described above, according to the present invention, the compressor 1
During operation, the first injection circuit 19 and the second injection circuit 20 both perform the injection operation, so that an abnormal rise in the discharge gas temperature in the compressor 1 is suppressed and the temperature of the lubricating oil returned to the compressor 1 is lowered. It is possible. Further, when the compressor 1 is stopped, even if the solenoid valve 18 is closed, the first and second injection circuits 19 and 20 are connected in series, so that the refrigerant in the cylinder of the compressor 1 is injected into the injection circuits 19 and 20. Two
It is possible to flow to the suction line side through 0, and liquid compression at the time of starting the compressor 1 thereafter can be prevented to achieve safe operation.

[Brief description of drawings]

FIG. 1 is a refrigeration circuit diagram in a refrigeration apparatus of an embodiment of the present invention.

FIG. 2 is a refrigeration circuit diagram in a conventional refrigeration system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 3 Condenser 4 Expansion mechanism 5 Evaporator 18 Solenoid valve 19 1st injection circuit 20 2nd injection circuit 21 1st capillary 22 2nd capillary 31 Refrigerant gas suction line 36 High pressure refrigerant liquid line

Claims (2)

[Claims] 1. A refrigeration system comprising a compressor 1, a condenser 3, an expansion mechanism 4 and an evaporator 5 to form a refrigeration cycle, the high pressure refrigerant liquid line being connected to a refrigerant inflow side of the expansion mechanism 4. 36 refrigerant liquid is introduced and decompressed by the first capillary 21,
A first injection circuit 19 for injecting into the intermediate pressure portion of the compressor 1, and a refrigerant liquid in the high-pressure refrigerant liquid line 36, which is decompressed by the second capillary 22 and connected to the refrigerant outflow side of the evaporator 5. The second injection circuit 20 for injecting into the gas suction line 31 and the first and second injection circuits 19, 20 are commonly used, and are provided in series connection with the first capillary 21 and the second capillary 22 on the upstream side, A refrigeration system including a solenoid valve 18 that is closed when the compressor 1 is stopped. 2. The refrigerating apparatus according to claim 1, wherein the electromagnetic valve 18 is opened to constantly inject the first and second injection circuits 19 and 20 during a refrigerating operation.